1. Field of the Invention
This invention relates to vacuum cleaners and in particular, relates to vacuum cleaners in which a reservoir of water is used to collect particulate matter.
2. Description of the Related Art
In many occupations, very fine dust particles are created that must be removed without removal or disturbance of other small items that are being handled or that are present in the dusty area. For example, in dental laboratories, trained technical personnel generally work near a vacuum source so that the airborne particulate matter that is created in large quantities is removed from the work area. Many vacuum systems used in such an environment cause the metal burs, crowns and dies to be removed if they come too close to the vacuum opening, because the systems have a very strong suction and remove both the fine dust particles and the larger pieces indiscriminately, and thus, cannot be used to remove only the fine particles. In addition, in many of these vacuum systems, the very fine dust particles are drawn into the vacuum cleaner bags and, because of their minute size, are ejected into the air again through the filter on the vacuum cleaner. This creates potential health problems for the workers who must continuously breathe in high levels of dust. The high vacuum present very near the worker's hands also causes the hands to become very cold because the heat from the hands is drawn off by the vacuum system.
To assist in selective dust removal, a variety of vacuum cleaners has been designed. Some of these cleaners use water to collect the dust that is picked up in the cleaner. In the Aqua-Vac cleaner (Teledyne Hanau, Buffalo, N.Y.), a squirrel cage fan on the motor blows directly on the water in the reservoir without agitating the water directly. The Rainbow cleaner (Rex-Air Corp., Troy, Mich.) provides a large amount of suction causing the water in its reservoir to be displaced somewhat and thus allowing more dust particles to be wetted by movement of the water than in the Aqua-Vac. The large amount of suction on the Rainbow cleaner causes larger particles as well as dust particles to be removed from an area.
In cleaners where the water is not agitated enough to allow dust particles to be wetted, a layer of dust particles may collect on top of the water with the remaining dust particles being carried back out into the environment. Dust particles may also accumulate on the fins of the fan causing the fan to decrease in efficiency and requiring continual cleaning maintenance of the fan and reservoir. Cleaners having a water reservoir with a motor directly above the water reservoir have the potential of water condensation, as well as the potential for splashing of water on the motor unless a barrier is placed between the motor and the water.
Standard shop vacuum cleaners that may be used to vacuum up water often have a valve that turns off if the water level reaches too high a level, thus minimizing the likelihood of water coming in contact with the electrical components. These cleaner are not designed to remove small dust particles selectively, however, without removing larger pieces and are not designed to retain the dust particles within the cleaner.
It is therefore an object of this invention to provide a vacuum cleaner that picks up fine dust particles without picking up larger particles.
It is a further object of this invention to provide a vacuum cleaner that removes dust particles from the air without returning them to the air.
It is a further object of this invention to provide a vacuum cleaner that may be used for extremely long periods of time without decreasing its ability to remove dust from the air.
It is a further object of this invention to provide a vacuum cleaner that does not pull in so much air that it causes significant cooling of hands placed in the area being cleaned.
It is a further object of this invention to provide a vacuum cleaner that is inexpensive to manufacture and that has easily obtainable parts.
It is a further object of the invention to provide a vacuum cleaner that may be easily maintained and requires little cleaning of the fan.
Other objects and advantages will be more fully apparent from the following disclosure and appended claims.